Chilled Beam Air Conditioning System

ABSTRACT

An improved chilled beam refrigeration and/or air conditioning systems uses a first chilled air flow to induce a second chilled air flow. Ambient air is drawn through first coils to produce a primary cooled air flow into an intake plenum on the suction side of a fan. The primary cooled air is drawn from the intake plenum, through the fan, and is exhausted into a discharge plenum at a positive pressure. Discharge nozzles along discharge face(s) of the discharge plenum direct the primary cooled air outward inducing a negative pressure in an area behind (or above) second coils. The negative pressure induces additional ambient air to be drawn through the second coils and cooled to provide additional cooled air. The additional cooled air mixes with the primary cooled air providing a larger refrigeration and/or air conditioning effect which would otherwise require additional motorized fans.

BACKGROUND OF THE INVENTION

The present invention relates to refrigeration and/or air conditioningsystems and in particular to chilled beam refrigeration and/or airconditioning systems.

Conventional refrigeration and/or air conditioning systems include acentral forced air unit with a fan circulating air through coils of anevaporator. The evaporator receives a flow of fluid refrigerant whichevaporates into a vapor refrigerant flow out of the evaporator andthereby drops in temperature. The air circulated through the evaporatoris cooled and then circulated throughout a house or other structure toprovide a flow of cooled air into various areas of the structure.Unfortunately, significant energy is required to circulate the cooledair throughout the structure.

Chilled beam refrigeration systems replace the circulation of the cooledair with circulation of cooled fluid. The cooled fluid is circulatedthrough a radiator (or heat exchanger), generally at a high point in aroom, making the radiator cold. Warm air rises and is cooled by the coldradiator, and falls back towards the floor. Less energy is required tocirculate the fluid and required outside air so an energy savingsresults.

A passive chilled beam uses the heavier cool air to induce a draftthrough a coil thus providing cooling or refrigeration to an area. Thesepassive types of coils can also be called “gravity coils” as they usethe draft induced by cooling air to cool a space. These devices may ormay not utilize drain pans to catch condensate in the event that thedewpoint of the coil is lower than that of the surrounding room.

An active chilled beam is a device that utilizes a duct in the centerthat is pressurized by an external source and has small holes or nozzlesto point out and away from the unit. The pressurized air at 0.4 to 1.0inches of water of positive static pressure induces additional air toflow through the coil. The amount of air induced as a result of thepressurized nozzles can vary from 1:1 ratio of pressurized air toinduced air flow up to six or eight times of induced air versus theamount of supplied pressurized air.

Unfortunately, while energy savings result from circulating liquid statefluid instead of air, the air flow through the radiator is often lessthan the optimal air flow for cooling the room.

BRIEF SUMMARY OF THE INVENTION

The present invention addresses the above and other needs by providingan improved chilled beam refrigeration and/or air conditioning systemswhich uses a first chilled air flow to induce a second chilled air flow.Ambient air is drawn through first coils to produce a primary cooled airflow into an intake plenum on the suction side of a fan. The primarycooled air is drawn from the intake plenum, through the fan, and isexhausted into a discharge plenum at a positive pressure. Dischargenozzles along discharge face(s) of the discharge plenum direct theprimary cooled air outward inducing a negative pressure in an areabehind (or above) second coils. The negative pressure induces additionalambient air to be drawn through the second coils and cooled to provideadditional cooled air. The additional cooled air mixes with the primarycooled air providing a larger refrigeration effect which would otherwiserequire additional motorized fans.

In accordance with one aspect of the invention, there is provided animproved chilled beam unit including the elements of an active chilledbeam unit in that the improved chilled beam unit includes nozzles toinduce airflow through secondary coil(s) while as the same time having afan integrated into the improved chilled beam unit to supply pressurizedair to the improved chilled beam unit so that the improved chilled beamunit is self contained.

In accordance with another aspect of the invention, there is provided animproved chilled beam unit which may include a drip pan to catch thecondensate depending on operating conditions.

In accordance with yet another aspect of the invention, there isprovided an improved chilled beam unit having one, two or three coilsfor primary and induced air paths.

In accordance with still another aspect of the invention, there isprovided an improved chilled beam unit configurable to have eitherunidirectional (for sidewall) or bidirectional airflow (for center ofroom locations).

In accordance with another aspect of the invention, there is provided animproved chilled beam unit having controls to modulate the fan speed todeliver specific air induction characteristics.

In accordance with still another aspect of the invention, there isprovided an improved chilled beam unit having controls to modulate thecoil temperature in relation to the dew point level of the room toprevent condensation.

In accordance with still another aspect of the invention, there isprovided an improved chilled beam unit utilizing either direct expansionor secondary heat transfer fluids.

In accordance with another aspect of the invention, there is provided animproved chilled beam unit having one or more fans to draw the primaryair flow to create the desired induced air flow.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The above and other aspects, features and advantages of the presentinvention will be more apparent from the following more particulardescription thereof, presented in conjunction with the followingdrawings wherein:

FIG. 1 is a prior art refrigeration and/or air conditioning system.

FIG. 2 shows a prior art distribution of cooled air through ducting tooutlets in various rooms.

FIG. 3 shows a prior art chilled beam system distributing cooled liquidstate fluid to chilled beam units in the various rooms.

FIG. 4 shows a prior art chilled beam unit.

FIG. 5A shows a side view of an improved chilled beam unit according tothe present invention and drip tray.

FIG. 5B shows an end view of the improved chilled beam unit according tothe present invention and drip tray.

FIG. 5C shows a bottom view of the improved chilled beam unit accordingto the present invention and drip tray.

FIG. 6A shows a side view of the improved chilled beam unit according tothe present invention with the drip tray removed.

FIG. 6B shows an end view of the improved chilled beam unit according tothe present invention with the drip tray removed.

FIG. 6C shows a bottom view of the improved chilled beam unit accordingto the present invention with the drip tray removed.

FIG. 7 shows a cross-sectional view of the improved chilled beam unitaccording to the present invention taken along line 7-7 of FIG. 6A.

FIG. 8 shows a primary air flow through the improved chilled beam unitaccording to the present invention.

FIG. 9 shows an induced air flow through the improved chilled beam unitaccording to the present invention.

Corresponding reference characters indicate corresponding componentsthroughout the several views of the drawings.

DETAILED DESCRIPTION OF THE INVENTION

The following description is of the best mode presently contemplated forcarrying out the invention. This description is not to be taken in alimiting sense, but is made merely for the purpose of describing one ormore preferred embodiments of the invention. The scope of the inventionshould be determined with reference to the claims.

A diagram showing a known refrigeration and/or air conditioning system10 is shown in FIG. 1. Typically, the compressor 12 compressesrefrigerant into a high-pressure vapor refrigerant flow 14 through apressure line 15 into a condenser 16. An outdoor fan 17 creates an airflow 19 a across the condenser 16 which cools the high-pressure vaporrefrigerant flow 14 by removing heat and condenses the high-pressurevapor flow 14 to a liquid state fluid refrigerant flow 18. The heatadded to the air flow 19 a produces a heated air flow 19 b. The liquidstate fluid refrigerant flow 18 flows along a refrigerant pipeline,through a metering device 26, and into an evaporator coil 20.

The metering device 26 controls the rate at which refrigerant enters theevaporator coil 20 and also creates a pressure drop. The pressure dropallows the refrigerant to expand from a small diameter tube to a largerdiameter. The liquid state fluid refrigerant flow 18 evaporates back toa vapor refrigerant flow 22 in the evaporator 20 experiencing atemperature drop. An evaporator fan 28 blows air 24 a across the coldevaporator coil 20 and heat transfers from the air flow 24 a into thecold vapor refrigerant flow 22 to provide a cooled air flow 24 b into aliving area. The vapor refrigerant flow 22 then returns to thecompressor 12 through a suction line 23 to start the cycle over again.

A prior art Heating, Ventilation, and Air Conditioning (HVAC) systemdistributes cooled or heated air from a central unit 32 through ducting34 to outlets 36 a, 36 b, and 36 c in various rooms 30 a, 30 b, and 30 cis shown in FIG. 2. The ducting 34 must be large to have sufficientcapacity with low restriction to air flow. The size of the ducting 34may limit installation of such systems to locations where substantialspace is available, and the large surface area of the ducting providesopportunities for leaks and damage.

A prior art chilled beam system distributing a cooled fluid from acentral unit 32 or an exterior unit 38 through lines 42 to chilled beamunits 40 a , 40 b, and 40 c in the various rooms 30 a, 30 b, and 30 cand return the fluid through lines 44 is shown in FIG. 3 and a prior artchilled beam unit 40 is shown in FIG. 4. The lines 42 and 44 are muchsmaller than the ducting 34 and allow installation in many morelocations. The chilled beam unit 40 may be active or passive andconducts heat or cold from the lines 42 to the ambient air 46 in theroom to provide heated or cooled air 48. Because of the much greatervolumetric heat capacity of liquid state fluids, the chilled beam unit40 provides fairly efficient operation.

The fluid may be a refrigerant which is in a liquid state in the lines42, evaporate to a gas state in coils in the chilled beam units, andreturns to the exterior unit 38 in the gas state, or a secondary fluidsuch as water or a water-glycol mixture, which remains in liquid stateat all times.

A side view of an improved chilled beam unit 50 according to the presentinvention and drip tray 54 is shown in FIG. 5A, an end view of thechilled beam unit 50 and drip tray 54 is shown in FIG. 5B, and a bottomview of the chilled beam unit 50 and drip tray 54 is shown in FIG. 5C.The drip tray 54 may include baffles 52 along its sides and bottom todirect an ambient air flow drawn into the improved chilled beam unit 50to prevent or reduce mixing of the air flows, or may simply includepassages with raised lips to trap condensation in the drip trays whileallowing the flow of ambient air. The drip pan 54 may or may not bepresent depending on the need to catch condensation on the coils.

A side view of the chilled beam unit 50 with the drip tray 54 removed isshown in FIG. 6A, an end view of the chilled beam unit 50 with the driptray removed is shown in FIG. 6B, a bottom view of the chilled beam unit50 with the drip tray removed is shown in FIG. 6C, and a cross-sectionalview of the chilled beam unit 50 taken along line 7-7 of FIG. 6A isshown in FIG. 7. The chilled beam unit 50 includes primary coils 66 a ona center bottom surface. Ambient room 46 a is drawn through the primarycoils 66 a into an intake plenum 70 by a fan (or blower) 62. The ambientair 46 a is either heated or cooled as it passes through the primarycoils 66 a providing a primary air flow 60 into the intake plenum 70.The primary air flow 60 is then drawn from the intake plenum 70 andblown into a discharge plenum 72 by the fan 62. The primary air flow 60then escapes the discharge plenum 72 through discharge ports 64.

The flow of discharged air 58 creates low pressure above the secondarycoils 66 b drawing additional ambient room air 46 b through thesecondary coils 66 b to create an induced air flow 56. The flow ofdischarged air 58 combines with the induced flow 56 to provide a greaterair flow than the primary air flow 60 without requiring an additionalfan, thus improving efficiency of the chilled beam unit 50. A two sidedchilled beam unit is shown in FIGS. 6A-7 which is suitable forpositioning in the center of a room or away from walls. A single sidedchilled beam unit 50 having one secondary coil 66 b and only one set ofdischarge ports 64 on one side of the chilled beam unit 50 is suitablefor mounting near or against a wall. The chilled beam unit 50 mayfurther include one, two, or three coils in the primary flow path and inthe induced air path(s), and the flow of the fluid through the coils maybe controlled as needed to control coil temperature in relation to duepoint to prevent condensation. The chilled beam unit 50 may utilizeeither refrigerants or chilled water/glycol mixtures as a heat transferfluid.

The primary coils 66 a are housed in a primary coil housing 67 a and thesecondary coils 66 b are housed in secondary coil housings 67 b. Theprimary coil housing 67 a is generally horizontal and the secondary coilhousings 67 b are tilted up from the horizontal at angle A. The angle Ais preferably between zero degrees and 60 degrees and preferablyapproximately 45 degrees.

The primary air flow 60 only through the chilled beam unit 50 is shownin FIG. 8. The ambient air 46 a is drawn into the chilled beam unit 50through the primary coils 66 a by low pressure in the intake plenum 70.The primary air flow then passes through the fan 62 and into thedischarge plenum 72, and out through the discharge ports 62 creating thedischarge flow 58.

The induced air flow through the chilled beam unit 60 is shown in FIG.9. The discharge flow 58 creates low pressure above the secondary coils68 b. The low pressure draws the ambient air 46 b through the secondarycoils 66 b to mix with the discharge flow 58 providing a greater flow ofheated or cooled air.

The fan 62 may be single speed or multi-speed to provide a specificprimary air flow. The chilled beam unit 50 may also include more thanone fan as needed.

While the invention herein disclosed has been described by means ofspecific embodiments and applications thereof, numerous modificationsand variations could be made thereto by those skilled in the art withoutdeparting from the scope of the invention set forth in the claims.

1. A Heating, Ventilation, and Air Conditioning (HVAC) system comprising: a source of cooled fluid; first lines carrying the cooled fluid from the source of cooled fluid; second lines returning the fluid to the source of cooled fluid; a chilled beam comprising: a housing having openings to receive a first flow of ambient air from an area the chilled beam resides in; coils residing in the housing and receiving the cooled fluid from the first lines and releasing the cooled fluid to the second lines; a fan urging the first flow of ambient air to pass through the coils to create a primary cooled air flow; discharge ports allowing the escape of the primary cooled air flow from the housing to create a flow of discharged air; a low pressure area next to the housing created by the flow of discharged air; and a second flow of ambient air into the housing, the low pressure area drawing the second flow of ambient air through the coils to create an induced flow from the housing; and the induced flow combining with the flow of discharged air to cool the room.
 2. The HVAC system of claim 1, wherein: the coils include first coils on a floor of the housing; and the first flow of ambient air passes through first coils.
 3. The HVAC system of claim 2, wherein: the coils include second coils on the side of the first coils; and the second flow of ambient air passes through the second coils.
 4. The HVAC system of claim 3, wherein: the second coils comprise coils residing on right and left sides of the first coils; and the second flow of ambient air passes through the second coils.
 5. The HVAC system of claim 4, wherein the second coils residing at a tilt of between zero and 60 degrees.
 6. The HVAC system of claim 5, wherein the second coils residing at a tilt of approximately 45 degrees.
 7. The HVAC system of claim 5, wherein; an inside edge of the second coils resides along edges of the first coils; and the second coils tilt up and away from the first coils.
 8. The HVAC system of claim 1, wherein: the first coils reside under an intake plenum running the length of the housing; a discharge plenum resides above the intake plenum and runs the length of the housing; the discharge ports reside along at least one side of the discharge plenum; and the fan resides between the intake plenum and the discharge plenum and draws air from the intake plenum and pushes the air into the discharge plenum.
 9. The HVAC system of claim 8, wherein the discharge ports reside along opposite sides of the discharge plenum.
 10. The HVAC system of claim 1, wherein the fluid is chilled water.
 11. The HVAC system of claim 1, wherein the fluid is a chilled water and glycol mixture.
 12. The HVAC system of claim 1, wherein the cooled fluid from the source of cooled fluid is a liquid state fluid refrigerant and the fluid returned to the source of cooled fluid is a gas state fluid refrigerant.
 13. A Heating, Ventilation, and Air Conditioning (HVAC) system comprising: a source of cooled fluid; first lines carrying the cooled fluid from the source of cooled fluid; second lines returning the fluid to the source of cooled fluid; a chilled beam comprising: an intake plenum having openings along the bottom to receive a first flow of ambient air from an area the chilled beam resides in; first coils residing in the bottom of the intake plenum and receiving the cooled fluid from the first lines and releasing the cooled fluid to the second lines; a discharge plenum residing above the intake plenum and running the length of the intake plenum; discharge ports reside along at least one side of the discharge plenum; a fan drawing a first flow of ambient air into the intake plenum and through the first coils, pushing the first flow into the discharge plenum and out through the discharge ports to create a flow of discharged air; a low pressure area next to the discharge plenum created by the flow of discharged air; second coils on at least one side of the intake plenum below the low pressure area; and a second flow of ambient air through the second coils, the low pressure area drawing the second flow of ambient air through the second coils to create an induced flow; and the induced flow combining with the flow of discharged air to cool the room.
 14. A Heating, Ventilation, and Air Conditioning (HVAC) system comprising: a source of cooled fluid; first lines carrying the cooled fluid from the source of cooled fluid; second lines returning the fluid to the source of cooled fluid; a chilled beam comprising: an intake plenum having openings along the bottom to receive a first flow of ambient air from an area the chilled beam resides in; first coils residing in the bottom of the intake plenum and receiving the cooled fluid from the first lines and releasing the cooled fluid to the second lines; a discharge plenum residing above the intake plenum and running the length of the intake plenum; discharge ports reside along opposite sides of the discharge plenum; a fan drawing a first flow of ambient air into the intake plenum and through the first coils, pushing the first flow into the discharge plenum and out through the discharge ports to create flows of discharged air on opposite sides of the discharge plenum; low pressure areas next to the discharge plenum created by the flows of discharged air; second coils on opposite sides of the intake plenum below the low pressure areas; and second flows of ambient air through the second coils, the low pressure areas drawing the second flows of ambient air through the second coils to create induced flows; and the induced flows combining with the flow of discharged air to cool the room. 